Metal attenuator grille for microphone

ABSTRACT

A metal attenuator grille for a microphone designed to obviate variations in the attenuation curve owing to environmental changes, comprising a solid metal member having a central opening and a plurality of spaced peripheral openings; the central opening, but not the peripheral openings, may be covered by a grille.

United States Patent [191 Knauert METAL ATTENUATOR GRILLE FOR MICROPHONE[75] Inventor: William F. Knauert, Yonkers, NY.

[73] Assigneei Gould Inc., Chicago, Ill.

[22] Filed: July 10, 1972 21 Appl. No.: 270,080

' 5 2 user; 181/3113,181/23,179/180 51 Int.Cl. H04r 1/28,l-104r25/00[58] Field of Search l8l/3l-B,,3l R, 23; 179/180,184,188,115,107 H,115.5

[56] References Cited UNITED STATES PATENTS 2,761,912 9/1956 Touger etal 181/31 B 2,840,178 6/1958 Boleslav 181/31 B Primary Examiner-StephenJ. Tomsky Attorney, Agent, or Firm-Ostrolenk, Faber, Gerb & Soffen I [57 ABSTRACT 4 Claims, 4 Drawing Figures 3,830,333 [45] Aug. 20, 1974PATENTEU 3.830.333

SHEEI 20! 2 drawings in which:

, METAL ATTENUATOR GRILLE FOR MICROPHONE The present invention relatesto a damping disc or grille for a microphone which will attenuate thesound reaching the microphone predictably and without variation.

Previously in order to modify the response curve of a microphone it hasbeen common to use metallic or plastic grills and textile or plasticattenuators. Thus one common practice was to use a plastic foamattenuator adjacent the microphone with a woven attenuator outwardlythereof succeeded by a plastic grille and protected by a wire grille.One of the problems was that the plastic foam or the woven attenuatorabsorbs moisture in humid atmospheres or as, a result of any atmosphericchanges and the effectiveness of the attenuator is thus considerablymodified.

The principal object of the present invention is to provide a means ofvmodifying the response curve to meet a specific specification withassurance that the response curve will not vary as a result ofenvironmental changes.

A further object of the present invention'is the replacement of priorattenuators which were capable of absorbing moisture, such as theplastic or woven attenuator, with a solid wall, preferably metallic,having a central opening and a plurality of additional smaller openingsspaced from the central opening to provide the appropriate responsecurve.;

Still a further object of the present invention is the utilization ofthe arrangement of the smaller openings spaced from the central openingto create a plurality of FIG. 1 is a side view of a behind the earhearing air having a microphone protected by a grille in accordance withthe present invention.

FIG. 2 is a plan view of the novel microphone grille.

FIG. 3 is a cross-sectional view through the novel microphone grilletaken on line 3-3 of FIG. 2.

FIG. 4 is a front view correspondingto that of FIG. 2 showing theapplication of grille cloth to the interior surface of the microphonegrille so that it covers the main central opening but not the peripheralopenings.

Referring now to F IG. 1, there is here shown a behdn the ear hearingaid having a microphone 11 therein protected and covered by the grille12 of the present invention. The grille 12 of FIGS. 2, 3 and 4 isprovided with a centralv opening 13 having a plurality of smalleropenings 14, 15 and 16 radially spaced from the central opening. Thecentral opening as seen in FIG. 4 is covered by a grille cloth 18 whichis'adhesively secured to respect to hearing aids-it of course has manywider applications and particularly to utilization in connection withmicrophones which are expected to be subject to environmental changes. v

In one application where the microphone is much larger than would beused in a behind the ear hearing aid, the relationship of the variousopenings to each other may be drawn from the following dimensionalelements: Where the round grille of FIGS. 2, 3 and 4 has a diameter ofthe order of 0.898 inches, the central opening 13 will have a diameterof the order of 0.152

inches. The peripheral openings 14, 15 and 16 are then spaced on acircle having the same center as the grille but 0.75 inches in diameterand the three openings 14, 15 and 16 have a diameter of 0.016 inches. Itwill thus be seen that the peripheral openings are approximatelyone'tenth the diameter of the main opening and the principal opening isof the order of one fifth the diameter of the grille measured to thecircle along which the peripheral openings are applied.

By this means therefore the difficulties which arosein connection withprior attenuators which are capable of absorbing moisture are obviatedand a simplified microphone attenuator grille is thereby provided.

In the foregoing the invention has been described in accordance with asingle illustrative embodiment. Since it is obvious that many variationsand modifications may be made within the scope of the disclosure it ispreferred that the invention described not be limited by the specificdisclosures herein but only by the appended claims.

The embodiments of the invention in which a specific privilege orproperty is claimed are defined as follows: 1. A microphone attenuatorcomprising a solid plate of nonporous non-absorbent material, having acentral opening and a plurality of additional relatively smalleropenings radially spaced from the central opening at a distance from theperiphery of the center opening greater than the diameter of the centralopening, said additional openings each having a diameter substantiallysmaller than that of the central opening and a grille cloth cover forthe central opening, the additional openings being free of said grillecloth.

2. The microphone attenuator grille of claim 9 in which the diameter ofeach of the additional openings is of the order of one tenth that of thecentral opening.

3. The microphone attenuator grille of claim 2 in which the additionalopenings are spaced at a radial distance from the. center of the centralopening along a circle having a diameter of the order offive times thediameter of the central opening.

4. The microphone attenuator grille of claim 3 in which the additionalopenings are three in number spaced apart.

1. A microphone attenuator comprising a solid plate of nonporousnon-absorbent material, having a central opening and a plurality ofadditional relatively smaller openings radially spaced from the centralopening at a distance from the periphery of the center opening greaterthan the diameter of the central opening, said additional openings eachhaving a diameter substantially smaller than that of the central openingand a grille cloth cover for the central opening, the additionalopenings being free of said grille cloth.
 2. The microphone attenuatorgrille of claim 9 in which the diameter of each of the additionalopenings is of the order of one tenth that of the central opening. 3.The microphone attenuator grille of claim 2 in which the additionalopenings are spaced at a radial distance from the center of the centralopening along a circle having a diameter of the order of five times thediameter of the central opening.
 4. The microphone attenuator grille ofclaim 3 in which the additional openings are three in number spaced 120*apart.